Question

I’m banging my head to the table in trying to write a regular expression that filter out strings that contain only Swedish letters, hyphens and single whitespaces – that is, not two in a row. I’ve got this preg_match('/^[A-ZÅÄÖa-zåäö-]+\s{1}$/',$b) and I feel like I’ve tried a hundred different models, but it’s not working. How would I accomplish this?

Answer 1

Often the best way to solve a problem like this is splitting it into two separate regular expression checks.

• check that the string contains only the letters you want (and whitespaces)
• if the first check passes, check that it doesn’t have two or more consecutive spaces

Try:

if ( preg_match('/^[A-ZÅÄÖa-zåäö-\s]$/',$b) && !preg_match('/\s\s+/', $b) ) {
    /...
}